In an Advanced Metering Infrastructure (AMI) network, a communication network can be employed to transmit messages between a back office system of a utility and meters that are deployed at customers' premises (e.g., homes, places of business, etc.). Examples of suitable communication networks include wireless mesh networks, cellular radio networks and power line carrier (PLC) networks.
In some known power distribution networks, an electric utility owns or contracts with power generation facilities, which produce the electric power that is initially carried to its customers over high voltage transmission lines. At substations, the voltage is stepped down and sent along distribution lines to transformers, which can be mounted, for example, on poles or in ground-level receptacles. From the transformers, the electric power travels along feeder lines to individual customers' premises, to be supplied to loads. At the premises, the amount of electric power that is consumed by the customer is measured with an electric meter.
The utility's AMI network may comprise communication nodes that are respectively associated with the electric meters. A communication node can be, for example, a Network Interface Card (NIC) that is incorporated within the structure of the electric meter itself. In one embodiment, the communication nodes can employ radio frequency (RF) signals to communicate with one another, and form a wireless mesh network. The communication nodes of the AMI network also communicate with one or more access points that provide for ingress and egress of the information to and from the mesh network. The access points communicate with the back office system of the utility, for example by means of a wide area network. In situations where the electric meters are sufficiently spaced that their respective communication nodes may not be able to directly communicate with one another, or with an access point, additional communication nodes that function as relays can be interspersed within the area of the wireless mesh network.
In other embodiments, different transmission media and/or network architectures may be employed to implement the AMI network.
In the above-described implementations, the communication network may be configured to communicate the topology of the utility distribution network, and thereby enable distribution equipment (e.g., substations, transformers, feeder lines, etc.) to be mapped to the downstream nodes that they service. For example, a communication node (e.g., a NIC) can be co-located with each item of distribution equipment (e.g., substation, transformer, etc.) to be mapped and monitored. A signaling technique can then be employed, for example by using one-way signaling over the power lines themselves, to associate each item of distribution equipment with the downstream nodes that it services. More detailed information regarding such mapping can be found in U.S. patent application Ser. No. 12/954,136, filed Nov. 24, 2010, the disclosure of which is incorporated herein by reference.
Another technique for mapping the topology of a communication network to that of a power distribution network may be to sample the voltage received at each customers' premises, and determine distribution equipment corresponding to information derived from the sampled voltage. For instance, the phase of the sampled voltage might be used to associate it with a particular substation or feeder line, as disclosed in U.S. Pat. No. 8,207,726, the disclosure of which is incorporated herein by reference.
While the topology of known communication networks may correspond to the topology of a utility's distribution network for delivering a resource, such as electricity, water or gas, to its customers, the back office system of the network may not become aware of a power outage (e.g., location, details, etc.) in a timely manner. For example, just prior to losing power, a communication node may be configured to transmit an outage notification (e.g., “last gasp”) upstream to a predetermined node. If the predetermined node is not also experiencing a loss in power, the predetermined node can forward the last gasp message upstream via other nodes until the message reaches the back office system. The utility system can, therefore, promptly identify and direct attention to the power outage area.
While this identification process can be effective when upstream nodes, to which last gasp messages are transmitted, are not also experiencing a loss in power, it is limited in various aspects. For example, if a transformer experiences a loss in power, each customer premises, to which it provides electricity, will also experience a loss in power. In other words, all distribution equipment (e.g., electric meters) downstream of the affected transformer will experience a power outage. Thus, if a predetermined communication node, at which a last gasp message is to be received, is also experiencing a loss in power (e.g., since it receives power from the same affected transformer), the last gasp message will not be forwarded upstream. In such a case, the back office system would not be promptly notified of the power outage and, therefore, the power outage area would not be promptly identified and/or addressed.
Thus, a need exists for an improved system and method for electrical gridpoint mapping and targeting of power outages that overcomes such issues with respect to the transmission of last gasp notifications.